Processes for preparing heterocyclic compounds including trans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2,1]octane-2-carboxamide and salts thereof

ABSTRACT

The present invention relates to compounds and processes for preparing compounds of Formula (I), 
     
       
         
         
             
             
         
       
         
         
           
             including compounds such as trans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2,1]octane-2-carboxamide and salts thereof (e.g., NXL-104).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/524,007, which claims priority under 35 U.S.C §119, based on U.S.Provisional Application Ser. No. 61/498,522 filed on Jun. 17, 2011, thedisclosures of both of which is are hereby incorporated by reference intheir entirety.

FIELD OF THE INVENTION

The present invention relates to novel compounds and processes forpreparing compounds of Formula (I), including compounds such astrans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2,1]octane-2-carboxamideand salts thereof (e.g., NXL-104).

BACKGROUND OF THE INVENTION

U.S. Pat. No. 7,112,592 discloses novel heterocyclic compounds and theirsalts, processes for making the compounds and methods of using thecompounds as antibacterial agents. One such compound is sodium salt oftrans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2,1]octane-2-carboxamide.PCT Application WO 2002/10172 describes the production of azabicycliccompounds and salts thereof with acids and bases, and in particular,trans-7-oxo-6-sulphoxy-1,6-diazabicyclo[3.2.1]octane-2-carboxamide andits pyridinium, tetrabutylammonium and sodium salts. PCT Application WO2003/063864 and U.S. Patent Publication No. 2005/0020572 describe theuse of compounds includingtrans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2, I]octane-2-carboxamidesodium salt, as β-lactamase inhibitors that can be administered alone orin combination with β-lactamine antibacterial agents. U.S. PatentPublication No. 2010/0197928 discloses methods for preparing2,5-disubstituted piperidine and novel intermediates. PCT Application WO2011/042560 and U.S. patent application Ser. No. 12/900,567 disclosecrystalline forms of trans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2,I]octane-2-carboxamide sodium salt. These references are incorporatedherein by reference, in their entirety.

There is an existing and continual need in the art for new and improvedmethods for preparing compounds of Formula (I) includingtrans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2,1]octane-2-carboxamide,related compounds and salts thereof (e.g., NXL-104). The presentinvention provides novel compounds and processes for preparing compoundsof Formula (I) including trans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2,I]octane-2-carboxamide, related compounds and salts thereof (e.g.,NXL-104).

SUMMARY OF THE INVENTION

According to some embodiments, the present invention provides processesfor preparing compounds of Formula (I):

and pharmaceutically acceptable salts, solvates, hydrates, enantiomersor diastereomers thereof (e.g., NXL-104) using compounds of Formula(II).

According to some embodiments, the present invention provides compoundsof Formula (III) and salts, solvates, hydrates, enantiomers ordiastereomers thereof (e.g.,(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxamide).

According to some embodiments, the present invention provides compoundsof Formula (VI) or salts or analogs thereof.

According to some embodiments, the present invention provides processesfor preparing a compound of Formula (IX).

According to some embodiments, the present invention provides processescompounds of Formula (XIV) or salts or analogs thereof.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides novel compounds and improved methods forpreparing compounds of Formula (I) and pharmaceutically acceptablesalts, solvates, hydrates, enantiomers or diastereomers thereof (e.g.,NXL-104).

In some embodiments, the processes comprise treating a compound ofFormula (II) with a source of nitrogen or an amine to prepare a compoundof Formula (III) and treating the compound of Formula (III) with aprotecting group and a carbonylation agent. In further embodiments, thetreatment is followed by deprotection.

In some embodiments, R1, R2, R3, R4, R5, R6 and R7 include, but are notlimited to, hydrogen, oxygen, nitrogen, amino, carbonyl, carbamoyl,alkyl, alkenyl, alkynyl, alkoxy, cylcoalkyl, aryl, aralkyl,trialkylsilyl and heterocycle groups. In specific embodiments, R1, R2,R3, R4, R5, R6 and R7 may be optionally substituted by one or morehalogen, oxygen, hydroxy, cyano, nitro, amino, alkylamino, dialkylamino,arylamino, diarylamino, amido, alkylamido, carbamoyl, ureido,dimethylamino, carboxyl, alkyl, allyl, halogenated alkyl, trialkylsilyl,alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, aryl, arylalkyl,heteroaryl, heteroarylalkyl, heterocycle, heterocyclealkyl, aroyl, acyl,alkoxy, aryloxy, heteroaryloxy, cycloalkyloxy, cycloalkylalkyloxy,arylalkyloxy, heteroarylalkyloxy, alkylhio, arylthio, alkylsulfinyl,alkylsulfonyl, arylsulfinyl, arylsulfonyl, heteroarylsulfinyl,heteroarylsulfonyl alkoxycarbonyl, aryloxycarbonyl,heteroaryloxycarbonyl or a combination thereof.

In other embodiments, R1 and R2 may together form a heterocycle. Theheterocycyle may be optionally substituted by one or more halogen,hydroxy, cyano, nitro, amino, alkylamino, dialkylamino, arylamino,diarylamino, amido, alkylamido, carbamoyl, ureido, dimethylamino,carboxyl, alkyl, halogenated alkyl, alkenyl, alkynyl, cycloalkyl,cycloalkylalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl,heterocycle, heterocyclealkyl, aroyl, acyl, alkoxy, aryloxy,heteroaryloxy, cycloalkyloxy, cycloalkylalkyloxy, arylalkyloxy,heteroarylalkyloxy, alkylhio, arylthio, alkylsulfinyl, alkylsulfonyl,arylsulfinyl, arylsulfonyl, heteroarylsulfinyl, heteroarylsulfonylalkoxycarbonyl, aryloxycarbonyl, heteroaryloxycarbonyl or a combinationthereof.

In still other embodiments, each of R3, R5 and R6 include COH, COB′,COOB′, CONH₂, CONHB′, CONHOH, CONHSO₂B′, CH₂COOH, CH₂COOB′, CH₂CONHOH,CH₂CONHCN, CH₂tetrazole, protected CH₂tetrazole, CH₂SO₃H, CH₂SO₂B′,CH₂PO(OB′)₂, CH₂PO(OB′)(OH), CH₂PO(B′)(OH) and CH₂PO(OH)₂. B′ includesan alkyl containing 1 to 6 carbon atoms optionally substituted by apyridyl or carbamoyl radical, —CH₂-alkenyl containing 3 to 9 carbonatoms, aryl containing 6 to 10 carbon atoms and aralkyl containing 7 to11 carbon atoms, wherein the nucleus of said aryl or aralkyl isoptionally substituted by OH, NH₂, NO₂, alkyl containing 1 to 6 carbonatoms, alkoxy containing 1 to 6 carbon atoms or by one or more halogenatoms.

In exemplary embodiments, R3, R5 or R6 may be OR′ or OP′.

R′ includes SO₃, SO₂, SO₂NHCOH, SO₂NHCO, SO₂NHCOO, SO₂NHCONH andSO₂NHCONH₂. In some embodiments, R′ may be substituted by hydrogen oralkyl group optionally substituted by a pyridyl or carbamoyl radical,—CH₂-alkenyl containing 3 to 9 carbon atoms, aryl containing 6 to 10carbon atoms and aralkyl containing 7 to 11 carbon atoms. The nucleus ofthe aryl or aralkyl may be substituted by OH, NH₂, NO₂, alkyl containing1 to 6 carbon atoms, alkoxy containing 1 to 6 carbon atoms or by one ormore halogen atoms.

P′ includes PO(OH)₂, PO₃, PO₂, PO, PO(OH)(O—), PO₂NHCOH, PO₂NHCO,PO₂NHCOO, PO₂NHCONH and PO₂NHCONH₂. In some embodiments, P′ may besubstituted by hydrogen or alkyl group optionally substituted by apyridyl or carbamoyl radical, —CH₂-alkenyl containing 3 to 9 carbonatoms, aryl containing 6 to 10 carbon atoms and aralkyl containing 7 to11 carbon atoms. The nucleus of the aryl or aralkyl is optionallysubstituted by OH, NH₂, NO₂, alkyl containing 1 to 6 carbon atoms,alkoxy containing 1 to 6 carbon atoms or by one or more halogen atoms.

In exemplary embodiments, R1 and R2 are hydrogen. In other embodiments,R1 is piperidinyl and R2 is hydrogen. In some examples, R3 is OSO₃H.

In some embodiments, R4 is benzyloxy. In other embodiments, R5 isbenzyloxy and R6 is hydrogen. In still other embodiments, R5 is allyl ortrialkylsilyl and R6 is hydrogen. In some examples, R7 is H. In otherembodiments, R7 is carbonyl, carbamoyl, or alkyl and may be optionallysubstituted by one or more halogen, oxygen, hydroxy, cyano, nitro,amino, alkylamino, dialkylamino, arylamino, diarylamino, amido,alkylamido, carbamoyl, ureido, dimethylamino, carboxyl, alkyl, allyl,halogenated alkyl, trialkylsilyl, alkenyl, alkynyl, cycloalkyl,cycloalkylalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl,heterocycle, heterocyclealkyl, aroyl, acyl, alkoxy, aryloxy,heteroaryloxy, cycloalkyloxy, cycloalkylalkyloxy, arylalkyloxy,heteroarylalkyloxy, alkylhio, arylthio, alkylsulfinyl, alkylsulfonyl,arylsulfinyl, arylsulfonyl, heteroarylsulfinyl, heteroarylsulfonylalkoxycarbonyl, aryloxycarbonyl, heteroaryloxycarbonyl or a combinationthereof. In specific embodiments, R7 is carbamoyl.

In exemplary embodiments, R4 and R5 are benzyloxy. In furtherembodiments, R6 and R7 are hydrogen.

The protecting group may be, for example, 9-fluorenylmethoxycarbonyl(FMOC) group, tert-butoxycarbonyl (BOC) group, benzyloxycarbonyl (CBZ),ethyl- or methyl-oxycarbonyl, phenoxycarbonyl, allyloxycarbonyl (ALOC)and equivalent groups known to one skilled in the art with the benefitof this disclosure. In specific embodiments, the protecting group is9-fluorenylmethoxycarbonyl (FMOC) group. In some embodiments, thecarbonylation agent may include a carbonyl with two leaving groups. Theleaving groups may be chloride or imidazole, for example, inN,N-carbonyl diimidazole (CDI). In further embodiments, the protectinggroup is removed resulting in cyclization.

In exemplary embodiments, the compounds formed after treatment ofcompounds of Formula (III) may further be treated with a SO₃ complex.

The compounds of Formula (II) may be prepared using compounds of Formula(IV).

R4 is as defined above. In some examples, the compounds of Formula (II)may be prepared according to Scheme I.

R may be R4, R5 or R6 as defined above. In some embodiments, P may be aprotecting group and includes 9-fluorenylmethoxycarbonyl (FMOC),tert-butoxycarbonyl (BOC), benzyloxycarbonyl (CBZ), ethyl- ormethyloxycarbonyl, phenoxycarbonyl, allyloxycarbonyl (ALOC) andequivalent groups known to one skilled in the art with the benefit ofthis disclosure. In exemplary embodiments, P may be tert-butoxycarbonyl(BOC).

In exemplary embodiments, base includes bases capable of deprotonatingtrimethylsulfoxonium iodide, for example, sodium hydride and potassiumtert-butoxide.

In exemplary embodiments, deprotection may include conditions thatremove protecting group P; cyclization may include conditions that bringabout a 6-exo-tet cyclization to yield a piperidine ring; reduction mayinclude conditions that cause reduction of the oxime bond to a singlebond, for example, with an R configuration; selective crystallizationmay include conditions that allow isolation of the desired isomer, forexample, an SR isomer, either as a salt or as the free base. An acid,which may be monovalent or bivalent, may be used to form a solid saltwith the desired product.

In some embodiments, a compound of Formula IV is ring-opened withtrimethylsulfoxoniumylide and then converted to the α-chloro-oxime in asingle step. The protecting group is removed and the compound iscyclized, the oxime is selectively reduced to a hydroxylamine, and acompound of Formula V is isolated, possibly as a salt.

The compound of Formula (V) may be used to preparetrans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2,1]octane-2-carboxamideand pharmaceutically acceptable salts thereof (e.g., NXL-104) accordingto Scheme II below. R4, R5 and R6 are as defined above.

In Scheme II, each of R1 and R2 may be hydrogen or alkyl group.

In exemplary embodiments, the piperidine nitrogen is protected, aphosgenation agent or carbonylation agent is used to install a carbonyl,and the protecting group is removed resulting in cyclization. Thehydroxylamine is deprotected, sulfated and converted to atetraalkylammonium salt.

In some embodiments, the present invention provides compounds of Formula(III) or salts, solvates, hydrates, enantiomers, diastereomers oranalogs thereof.

The R1, R2, R3, R4, R5, R6 and R7 groups are as described above. In someembodiments, R1, R2, R6 and R7 are H and R5 is benzyloxy. For example,the present invention provides compounds of Formula (VI) or salts oranalogs thereof.

In exemplary embodiments, the present invention provides compounds ofFormula (VII):

R1, R2, R3, R4, R5, R6 and R7 may be any combination of the groups asdescribed above.

In exemplary embodiments, R1, R2 and R6 are hydrogen, R5 is OSO₃H and R7is carbamoyl. In other examples, R1 is piperidinyl, R2 and R6 arehydrogen, R5 is OSO₃H, and R7 is carbamoyl.

In another aspect, the present invention provides processes forpreparingtrans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2,1]octane-2-carboxamideand salts thereof (e.g., NXL-104).

In specific embodiments, the present invention provides methods formaking compounds of Formula (VIII) or pharmaceutically acceptable saltsthereof (e.g., NXL-104).

NXL-104 may also be referred to as monosodium salt of(1R,2S,5R)-7-oxo-6-sulphoxy-1,6-diazabicyclo[3.2.1]octane-2-carboxamide,avibactam or sodium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl)oxidanide.The structure of NXL-104 is represented below (Formula IX).

In one aspect, the present invention provides methods for makingtrans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2,1]octane-2-carboxamideand pharmaceutically acceptable salts thereof (e.g., NXL-104) usingcompounds according to Scheme III below.

R8 and R9 include any of the groups in any combination as defined for R1to R7 groups above.

In some embodiments, a compound of Formula (X) is ring-opened withtrimethylsulfoxoniumylide and converted to the α-chloro-oxime in asingle step.

The protecting group is removed and the compound is cyclized, the oximeis selectively reduced to a hydroxylamine, and a compound of Formula(XI) is isolated, possibly as a salt.

In some embodiments, R8 includes alkyl, allyl, aryl, heteroaryl, benzyl,alkoxyalkyl, arylalkoxyalkyl or combinations thereof, and equivalentgroups known to one skilled in the art with the benefit of thisdisclosure. R8 may be a substituted or an unsubstituted alkyl group,which may be linear or branched. For example, R8 may be a methyl, ethyl,propyl, isopropyl, butyl, pentyl or hexyl group. In other embodiments,R8 may be an aryl or an aromatic group. For example, R8 may be a phenyl,naphthyl or furyl group. In exemplary embodiments, R8 may be a benzyl ora substituted benzyl.

In some embodiments, R9 may be a protecting group including alkyl,allyl, acyl, benzyl, H or silyl protecting groups or combinationsthereof and equivalent groups known to one skilled in the art with thebenefit of this disclosure. For example, R9 may be an allyl,trialkylsilyl or a benzyl group. In exemplary embodiments, R9 may be abenzyl group.

In some embodiments, P may be a protecting group and includes9-fluorenylmethoxycarbonyl (FMOC), tert-butoxycarbonyl (BOC),benzyloxycarbonyl (CBZ), ethyl- or methyloxycarbonyl, phenoxycarbonyl,allyloxycarbonyl (ALOC) and equivalent groups known to one skilled inthe art with the benefit of this disclosure. In exemplary embodiments, Pmay be tert-butoxycarbonyl (BOC).

In exemplary embodiments, base includes bases capable of deprotonatingtrimethylsulfoxonium iodide, for example, sodium hydride and potassiumtert-butoxide.

In exemplary embodiments, deprotection includes conditions that removeprotecting group P; cyclization includes conditions that bring about a6-exo-tet cyclization to yield a piperidine ring; reduction includesconditions that cause reduction of the oxime bond to a single bond,preferably with an R configuration; selective crystallization includesconditions that allow isolation of the desired isomer, for example, anSR isomer, either as a salt or as the free base. An acid, which may bemonovalent or bivalent, may be used to form a solid salt with thedesired product.

One skilled in the art will understand with the benefit of thisdisclosure that that compounds of Formula (X) can be used to preparecompounds of Formula (XI) using conditions and reagents that may yieldalternative compounds as intermediates. For example, chlorooxime may beprepared via compounds of Formula (XII) and (XIII) including free base,salts and enantiomers thereof.

In exemplary embodiments, chloro-oxime may be prepared according toScheme IV below.

In exemplary embodiments, compounds of Formula (XI) may be used topreparetrans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2,1]octane-2-carboxamideand pharmaceutically acceptable salts thereof (e.g., NXL-104) accordingto Scheme V below.

In some embodiments, a compound of Formula (XI) is converted to acompound of Formula (XIV) using an ammonia source.

The piperidine nitrogen is protected, a phosgenation or carbonylationagent is used to install a carbonyl, and the protecting group is removedresulting in cyclization. The hydroxylamine is deprotected, sulfated andconverted to a tetraalkylammonium salt. The tetraalkylammonium salt issubjected to ion exchange to provide a pharmaceutically acceptable saltof(1R,2S,5R)-7-oxo-6-sulphooxy-1,6-diazabicyclo[3.2.1]octane-2-carboxamide.

In some embodiments, R8 includes alkyl, allyl, aryl, heteroaryl, benzyl,alkoxyalkyl, arylalkoxyalkyl or combinations thereof, and equivalentgroups known to one skilled in the art with the benefit of thisdisclosure. R8 may be a substituted or an unsubstituted alkyl group,which may be linear or branched. For example, R8 may be a methyl, ethyl,propyl, isopropyl, butyl, pentyl or hexyl group. In other embodiments,R8 may be an aryl or an aromatic group. For example, R8 may be a phenyl,naphthyl or furyl group. In exemplary embodiments, R8 may be a benzyl ora substituted benzyl.

In some embodiments, R9 may be a functional group suitable for theprotection of hydroxylamines. Examples of suitable R9 groups includealkyl, allyl, acyl, benzyl, H or silyl protecting groups or combinationsthereof and equivalent groups known to one skilled in the art with thebenefit of this disclosure. In some embodiments, R9 may be an allyl,trialkylsilyl or a benzyl group. In exemplary embodiments, R9 may be abenzyl group.

In exemplary embodiments, NH₃ may be ammonia, a source of ammonia, or anammonia proxy. For example, ammonia proxy may be formamidine and a base.In some embodiments, the ammonia may be dissolved in a polar solventsuch as methanol, water, isopropanol and dioxane.

In exemplary embodiments, PG includes a protecting group, LG includes aleaving group; deprotection includes conditions for the removal of theprotecting group; SO₃ complex includes a sulfur trioxide complex; and(R10)₄N⁺ source includes a tetra n-alkylammonium ion source.

The protecting group may be, for example, 9-fluorenylmethoxycarbonyl(FMOC) group, tert-butoxycarbonyl (BOC) group, benzyloxycarbonyl (CBZ),ethyl- or methyl-oxycarbonyl, phenoxycarbonyl, allyloxycarbonyl (ALOC)and equivalent groups known to one skilled in the art with the benefitof this disclosure. In specific embodiments, the protecting group is9-fluorenylmethoxycarbonyl (FMOC) group.

The leaving group may be an imidazole, for example, in N,N-carbonyldiimidazole (CDI).

Deprotection includes conditions for the removal of the protecting groupR9, for example, hydrogenation if R9 is benzyl. The SO₃ complex may besulfur trioxide complex such as SO₃.pyridine, SO₃.dimethylformamide,SO₃.triethylamine, SO-₃.trimethylamine, chlorosulfonic acid and oleum.

The (R₁₀)₄N⁺ source may be a tetra n-alkylammonium ion source, such astetraethylammonium chloride, tetramethylammonium hydroxide,tetrabutylammonium acetate and tetrabutylammonium bisulphate.

The ion exchange step converts the tetralkylammonium salt to apharmaceutically acceptable salt, e.g., sodium, potassium, calcium andmagnesium. This can be accomplished by crystallization of the salt,e.g., the sodium salt using a source of sodium that may be any salt orform of sodium that allows ion exchange with the tetraalkylammonium. Thesodium source may be a sodium carboxylate salt, or an ion exchange resincontaining sodium. In exemplary embodiments, the sodium source is sodium2-ethylhexanoate.

Alternatively, other pharmaceutically acceptable salts of(1R,2S,5R)-7-oxo-6-sulphooxy-1,6-diazabicyclo[3.2.1]octane-2-carboxamidemay be prepared in analogous fashion. For example, the potassium saltmay be prepared using soluble potassium salts.

In specific embodiments, sodium salt of(1R,2S,5R)-7-oxo-6-sulphooxy-1,6-diazabicyclo[3.2.1]octane-2-carboxamideis prepared using benzyl(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate (1:1)using Scheme VI.

In exemplary embodiments, compounds described herein, for example,benzyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) may be treated with ammonia dissolved in a polar solvent such asmethanol, water, isopropanol or dioxane. After removal of anyby-product, the mixture may be crystallized from a non-polar solvent.Examples of suitable solvents are toluene, cyclopentyl methyl ether(CPME), methyl tert-butyl ether (MTBE), and isohexane.(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxamide (amide) may beprotected at the piperidine nitrogen with a protecting group prior tothe addition of a phosgenation or carbonylation agent, beforedeprotecting the piperidine nitrogen, cyclizing under basic conditionsand isolating the product by crystallization. The protecting group maybe FMOC, BOC or CBZ and may be provided in an organic solvent such astoluene, chlorobenzene or fluorobenzene. Examples of suitablephosgenation or carbonylation agents are CDI, phosgene and triphosgene.For the deprotection of an FMOC protecting group, examples of suitablereagents are diethylamine, piperidine, and morpholine. Deprotection ofother protecting groups can be accomplished using methods known to thoseskilled in the art with the benefit of this disclosure. Examples ofbases for the cyclization include diethylamine, piperidine, morpholinetriethylamine, diisopropylethylamine and aqueous bases such as sodiumbicarbonate solution.

(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamidemay further be debenzylated by treatment with hydrogen in the presenceof a catalyst (such as palladium, platinum, rhodium, nickel) and in thepresence of a base (such as a triethylamine, diisopropylethylamine) anda source of SO₃ (such as SO₃.pyridine, SO-₃.dimethylformamide,SO₃.triethylamine, SO₃.trimethylamine) and a solvent (such as methanol,ethanol, isopropanol, propanol, butanol, water or mixtures of the same).The product may then be treated with a tetrabutylammonium ion source(such as tetrabutylammonium acetate, tetrabutylammonium bisulphate),extracted into an organic solvent and crystallized from an organicsolvent (such as methyl isobutyl ketone (MIBK), acetone,isopropylacetate).

Tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanideis then dissolved in a solvent (such as ethanol, isopropanol, propanol,water or mixtures of the same) and treated with a sodium carboxylatesalt (such a sodium-2-ethylhexanoate).

In another aspect, sodium salt of(1R,2S,5R)-7-oxo-6-sulphooxy-1,6-diazabicyclo[3.2.1]octane-2-carboxamidemay be prepared using compounds according to Scheme VII.

In the presence of base, compound of Formula (XI) reacts with aphosgenation or carbonylation agent to give the cyclic urea. The esterprotecting group is removed and the resulting acid is converted to acarboxamide. The hydroxylamine is deprotected, sulfated and converted toa tetraalkylammonium salt. The tetraalkylammonium salt is subjected toion exchange to provide a pharmaceutically acceptable salt of(1R,2S,5R)-7-oxo-6-sulphooxy-1,6-diazabicyclo[3.2.1]octane-2-carboxamide.

R8 and R9 may represent groups as described above. In specificembodiments, base includes a base for the deprotonation of benzyl(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate (1:1),for example, an inorganic base, such as KHCO₃, or an organic base, suchas triethylamine, 3-picoline, pyridine and lutidine; carbonylationincludes an addition of a carbonyl group using a single reagent (e.g.triphosgene, N,N-carbonyl diimidazole (CDI), C(O)(SMe)₂) or acombination of reagents (e.g provided in the scheme discussed above, oruse of CO₂ and chlorotrimethylsilane, followed by SOCl₂ and pyridine);hydrolysis includes selective cleavage of the CO bond to liberate R70,for example, using tetrabutylammonium hydroxide (TBAOH), LiOH, NaOH,iodotrimethylsilane (TMSI). Alternatively, this step can be replaced byother deprotection conditions, for example, when R8=CH₂C₆H₅,hydrogenation, or if R8=allyl, isomerization with Pd; amidation includesthe activation of acidic functionality followed by quenching with anammonia source, either sequentially or concurrently. For example, theacid may be activated using such reagents as alkyl chloroformates,trimethylacetyl chloride, thionyl chloride, diethylchlorophosphate, CDI.The resulting activated acid may be quenched with ammonia or solutions,salts, or sources of ammonia, or with an ammonia proxy such ashexamethyldisilazane (HMDS). Alternatively, the activation and quenchmay be concurrent using such reagent combinations as diimides, forexample, N,N′-dicyclohexylcarbodiimide (DCC) andN-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) or1-propanephosphonic acid cyclic anhydride with HMDS; deprotectionincludes removal of the R9 protecting group to give the freehydroxylamine; sulfatation includes addition of an SO₃ group to ahydroxy group using a source of SO₃, e.g., SO₃.DMF, SO₃.NMe₃ and CISO₃H;salt formation includes addition of a tetra n-alkylammonium ion source,for example, tetra n-butylammonium acetate, and isolation of theresulting salt.

In some embodiments, deprotection may be achieved using methods known tothose skilled in the art with the benefit of this disclosure. Forexample, hydrogenation using a palladium catalyst may be used if R9 isbenzyl.

In another aspect of the invention,(1R,2S,5R)-7-oxo-6-sulphooxy-1,6-diazabicyclo[3.2.1]octane-2-carboxamidemay be prepared using a compound of Formula (XV).

These compounds of Formula (XV) may be prepared according to SchemeVIII.

A compound of Formula (XVI) is ring-opened with trimethylsulfoxoniumylide and converted to the α-chloro-oxime.

The protecting group is removed and the compound is cyclized, the oximeis selectively reduced to a hydroxylamine, and the final compound isisolated, possibly as a salt. In some embodiments, R8 includes anyalkyl, allyl, aryl, benzyl, heterocyclic and equivalent groups for theprotection of carboxamides known to one skilled in the art with thebenefit of this disclosure. In specific embodiments, R8 may be atert-butyl, benzyl, allyl, methoxymethyl, silyl, tetrahydropyran orsiloxyalkyl group. In exemplary embodiments, R8 may be a benzyl or asubstituted benzyl.

In some embodiments, R9 may be a protecting group including alkyl,allyl, acyl, benzyl, H or silyl protecting groups and equivalent groupsknown to one skilled in the art with the benefit of this disclosure. Forexample, R9 may be an allyl, trialkylsilyl, or preferably a benzylgroup.

In exemplary embodiments, P may be a protecting group, for example, acarbamate protecting group such as tert-butoxycarbonyl (BOC) orbenzyloxycarbonyl.

In exemplary embodiments, base in Step 1 includes bases capable ofdeprotonating trimethylsulfoxonium iodide, for example, sodium hydrideand potassium tert-butoxide.

In exemplary embodiments, deprotection includes conditions that removeprotecting group P; cyclization includes conditions that bring about a6-exo-tet cyclization to yield a piperidine ring; reduction includesconditions that cause reduction of the oxime bond to a single bond,preferably with an R configuration; selective crystallization includesconditions that allow isolation of the desired SR isomer, either as asalt or as the free base. An acid, which may be monovalent or bivalent,may be used to form a solid salt with the desired product.

The compounds obtained using the scheme discussed above may be used toprepare sodium salt of(1R,2S,5R)-7-oxo-6-sulphooxy-1,6-diazabicyclo[3.2.1]octane-2-carboxamideaccording to Scheme IX.

A compound of Formula (XV) is converted to the urea, which is thendeprotected, sulfated and converted to the tetraalkylammonium salt. Thetetraalkylammonium salt is subjected to ion exchange to provide apharmaceutically acceptable salt of(1R,2S,5R)-7-oxo-6-sulphooxy-1,6-diazabicyclo[3.2.1]octane-2-carboxamide.R7 and R9 groups are as defined above. Phosgenation or carbonylation isthe addition of a carbonyl using either a single reagent, e.g.,triphosgene, CDI, or combination of reagents, such as those described inthe Schemes above. Deprotection includes the removal of R8 and R9,either concurrently or sequentially. Other steps have been describedelsewhere.

In some embodiments,trans-7-oxo-6-(sulphooxy)-1,6-diazabicyclo[3,2,1]octane-2-carboxamideand salts thereof (e.g., NXL-104) may be prepared using enzymes. Forexample, the processes may involve making a compound of Formula (XVII).

The compound (Formula XVII) may be prepared according to Scheme X.

In some embodiments, R8 includes, but is not limited to, alkyl groups,aryl groups, and benzyl groups. In exemplary embodiments, R8 may be analkyl group. For example, R8 may be methyl or ethyl.

In some embodiments, R9 may be a functional group suitable for theprotection of hydroxylamines. For example, R9 may be an allyl,trialkylsilyl, or a benzyl group.

In exemplary embodiments, phosgenation or carbonylation may be performedwith a phosgenating agent, such as triphosgene.

In exemplary embodiments, enzymatic amidation is performed using aenzyme. For example, Candida antarctica Lipase A or Candida antarcticaLipase B, in the presence of an ammonia source such as ammoniumcarbamate, ammonia, ammonium chloride or hexamethyldisilazane and asolvent such as acetonitrile, dioxane or chlorobutane.

The processes described herein may be useful for preparing compounds insufficient purity without isolation. For example, the use of a base(such as potassium tert-butoxide) may yield sufficiently pure beta-ketosulfoxonium (BKS) that could be used in subsequent steps without a needfor isolation. In some embodiments, the processes may involve a singlestep conversion using a single solvent and a single reagent. Forexample, beta-keto sulfoxonium may be converted to chloroxime in asingle solvent with a single reagent. In other embodiments, theprocesses may use improved reduction conditions that may give a higherratio of a desired SR isomer to an undesired SS isomer. For example, theratio may be more than 1. In some embodiments, the ratio of the desiredSR isomer to the undesired SS isomer may range from 1 to 10. Inexemplary embodiments, the ratio may be 4. In still other embodiments,the processes may provide improved crystallization conditions that mayallow selective isolation of desired SR isomer in high purity. In someembodiments, the processes may provide a high yield of pure intermediatecompounds, thus, obviating the need to isolate the intermediates. Forexample, the processes described herein may provide a very high yield ofpure benzyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylateethanedioate (1:1). In such cases, isolation of intermediates may not benecessary.

The processes described herein may provide compounds in unexpected highyields and may thus, be efficient and cost-effective.

Unless defined otherwise, all technical and scientific terms used hereingenerally have the same meaning as commonly understood by one ofordinary skill in the art to which this invention belongs.

“NXL-104” refers to the monosodium salt of(1R,2S,5R)-7-oxo-6-sulphooxy-1,6-diazabicyclo[3.2.1]octane-2-carboxamideor alternatively, sodium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl)oxidanideor avibactam, and is represented by structure shown below.

As used herein the term “halogen” means F, Cl, Br, and I.

The term “alkyl” means a substituted or unsubstituted saturatedhydrocarbon radical which may be straight-chain or branched-chain andmay comprise about 1 to about 20 carbon atoms, for instance 1 to 12carbon atoms, such as 1 to 8 carbon atoms, e.g., 1 to 4 carbon atoms.Suitable alkyl groups include, but are not limited to, methyl, ethyl,propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl,octyl, nonyl, decyl, undecyl, and dodecyl. Other examples of suitablealkyl groups include, but are not limited to, 1-, 2- or 3-methylbutyl,1,1-, 1,2- or 2,2-dimethylpropyl, 1-ethylpropyl, 1-, 2-, 3- or4-methylpentyl, 1,1-, 1,2-, 1,3-, 2,2-, 2,3- or 3,3-dimethylbutyl, 1- or2-ethylbutyl, ethylmethylpropyl, trimethylpropyl, methylhexyl,dimethylpentyl, ethylpentyl, ethylmethylbutyl, dimethylbutyl, and thelike.

Substituted alkyl groups are alkyl groups as described above which aresubstituted in one or more positions by, e.g., halogen, hydroxyl, amino,carboxy, alkylamino, dialkylamino, aryl, heteroaryl, alkoxy, nitro andcyano, and combinations thereof.

The term “halogenated alkyl” means a saturated hydrocarbon radical whichmay be straight-chain or branched-chain and may comprise about 1 toabout 20 carbon atoms, for instance 1 to 12 carbon atoms, such as 1 to 8carbon atoms, e.g., 1 to 4 carbon atoms, that is substituted by one ormore halogens, such as, but not limited to, —CF₃, CF₂CF₃, CHF₂, CH₂F,and the like. The use of the term “halogenated alkyl” should not beconstrued to mean that a “substituted alkyl” group may not besubstituted by one or more halogens.

The term “alkenyl” means a substituted or unsubstituted hydrocarbonradical which may be straight-chain or branched-chain, which containsone or more carbon-carbon double bonds, and which may comprise about 1to about 20 carbon atoms, such as 1 to 12 carbon atoms, for instance 1to 6 carbon atoms. Suitable alkenyl groups include ethenyl, propenyl,butenyl, etc.

Substituted alkenyl groups are alkenyl groups as described above whichare substituted in one or more positions by, e.g., halogen, hydroxyl,amino, carboxy, alkylamino, dialkylamino, aryl, heteroaryl, alkoxy,nitro and cyano, and combinations thereof.

The term “alkylene” means a linear saturated divalent hydrocarbonradical of one to six carbon atoms or a branched saturated divalenthydrocarbon radical of three to six carbon atoms unless otherwise statede.g., methylene, ethylene, propylene, 1-methylpropylene,2-methylpropylene, butylene, pentylene, and the like.

The term “alkynyl” means a substituted or unsubstituted aliphatichydrocarbon radical which may be straight-chain or branched-chain andwhich contains one or more carbon-carbon triple bonds. Preferably, thealkynyl group contains 2 to 15 carbon atoms, such as 2 to 12 carbonatoms, e.g., 2 to 8 carbon atoms. Suitable alkynyl groups includeethynyl, propynyl, butynyl, etc.

Substituted alkynyl groups are alkynyl groups as described above whichare substituted in one or more positions by, e.g., halogen, hydroxyl,amino, carboxy, alkylamino, dialkylamino, aryl, heteroaryl, alkoxy,nitro and cyano, and combinations thereof.

The term “amino” means —NH₂.

The term “alkylamino” means —NH(alkyl), wherein alkyl is as describedabove.

The term “dialkylamino” means —N(alkyl)₂, wherein alkyl is as describedabove.

The term “aryl” means a substituted or unsubstituted aromatic monocyclicor bicyclic ring system comprising about 5 to about 14 carbon atoms,e.g., about 6 to about 10 carbon atoms. Suitable aryl groups include,but are not limited to, phenyl, naphthyl, anthracenyl.

Substituted aryl groups include the above-described aryl groups whichare substituted one or more times by, for example, but not limited to,halogen, hydroxyl, amino, carboxy, alkylamino, dialkylamino, aryl,heteroaryl, alkoxy, nitro and cyano, and combinations thereof.

The term “arylamino” means —NH(aryl), wherein aryl is as describedabove.

The term “diarylamino” means —N(aryl)₂, wherein aryl is as describedabove.

The term “amido” means —CONH₂.

The term “arylalkyl” refers to an -(alkylene)-aryl group in which thearyl and alkylene portions are in accordance with the previousdescriptions. Suitable examples include, but are not limited to, benzyl,1-phenethyl, 2-phenethyl, phenpropyl, phenbutyl, phenpentyl, andnapthylmethyl.

The term “carboxyl” means —C(O)OH.

The term “cycloalkyl” means a monocyclic, bicyclic or tricyclicnonaromatic saturated hydrocarbon radical having 3 to 10 carbon atoms,such as 3 to 8 carbon atoms, for example, 3 to 6 carbon atoms. Suitablecycloalkyl groups include, but are not limited to, cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, norbornyl,1-decalin, adamant-1-yl, and adamant-2-yl. Other suitable cycloalkylgroups include, but are not limited to, spiropentyl,bicyclo[2.1.0]pentyl, bicyclo[3.1.0]hexyl, spiro[2.4]heptyl,spiro[2.5]octyl, bicyclo[5.1.0]octyl, spiro[2.6]nonyl,bicyclo[2.2.0]hexyl, spiro[3.3]heptyl, bicyclo[4.2.0]octyl, andspiro[3.5]nonyl. Preferred cycloalkyl groups include cyclopropyl,cyclobutyl, cyclopentyl and cyclohexyl. The cycloalkyl group can besubstituted, for example, by one or more halogens and/or alkyl groups.

The term “cycloalkylalkyl” means a -(alkylene)-cycloalkyl in which thecycloalkyl group is as previsouly described; e.g., cyclopropylmethyl,cyclobutylmethyl, cyclopentylethyl, or cyclohexylmethyl, and the like.

The term “heteroaryl” means a substituted or unsubstituted aromaticmonocyclic or multicyclic ring system comprising 5 to 14 ring atoms,preferably about 5 to about 10 ring atoms and most preferably 5 or 6ring atoms, wherein at least one of the ring atoms is an N, O or S atom.Suitable heteroaryl groups include, but are not limited to furyl,thienyl, pyrrolyl, pyrazolyl, imidazolyl, pyridyl, pyrimidinyl,benzimidazolyl, indazolyl, indolyl, quinolinyl, isoquinolinyl,naphthyridinyl and the like.

Substituted heteroaryl groups include the above-described heteroarylgroups which are substituted one or more times by, for example, but notlimited to, halogen, hydroxyl, amino, carboxy, alkylamino, dialkylamino,aryl, heteroaryl, alkoxy, nitro and combinations thereof.

The term “heteroarylalkyl” refers to a -(alkylene)-heteroaryl groupwherein the heteroaryl and alkylene portions are in accordance with theprevious descriptions. Suitable examples include, but are not limitedto, pyridylmethyl, thiazolylmethyl, thienylmethyl, pyrimidinylmethyl,pyrazinylmethyl, and isoquinolinylmethyl, and the like.

The term “heterocycle” means a substituted or unsubstituted non-aromaticmono- or multicyclic ring system comprising 3 to 10 atoms, preferably 5or 6, wherein at least one of the ring atoms is an N, O or S atom.Suitable heterocyle groups include, but are not limited totetrahydrofuranyl, tetrahydrothienyl, tetrahydropyranyl, dihydropyranyl,pyrrolidinyl, piperidinyl, piperazinyl, thiomorpholinyl, morpholinyl,isoxazolinyl, and the like.

Substituted heterocycle groups include the above-described heterocyclegroups which are substituted one or more times by, for example, halogen,amino, alkyl, hydroxy, carboxy, and combinations thereof. Heterocyclegroups may also be substituted by, e.g., aryl or heteroaryl.

The term “heterocyclealkyl” refers to a -(alkylene)-heterocycle groupwherein the heterocycle and alkylene portions are in accordance with theprevious discussions.

The term “aroyl” means an aryl-C(O)—, in which the aryl group is aspreviously described. Suitable aroyl groups include, but are not limitedto, benzoyl and 1-naphthoyl.

The term “acyl” means an HC(O)—, alkyl-C(O)—, cycloalkyl-C(O)—,aryl-C(O)—, or heteroalkyl-C(O)—, in which the various groups are aspreviously described, e.g., acetyl, propionyl, benzoyl,pyridinylcarbonyl, and the like.

The term “alkoxy” means alkyl-O— groups in which the alkyl portion is inaccordance with the previous descriptions. Suitable alkoxy groupsinclude, but are not limited to, methoxy, ethoxy, n-propoxy,iso-propoxy, n-butoxy, t-butoxy, pentoxy, hexoxy, heptoxy, octoxy, andthe like. For example, the alkoxy can be methoxy or ethoxy.

The term “aryloxy” means an aryl-O— group, in which the aryl group is aspreviously described.

The term “heteroaryloxy” means an heteroaryl-O— group, in which theheteroaryl group is as previously described.

The term “cycloalkylalkyloxy” means a —O-(alkylene)-cycloalkyl group, inwhich the cycloalkyl and alkylene groups are as previously described.

The term “alkylthio” means an alkyl-S— group, in which the alkyl groupis as previously described.

The term “arylthio” means an aryl-S— group, in which the aryl group isas previously described.

The term “alkylsulfinyl” means a —SOR radical where R is alkyl asdefined above, e.g., methylsulfinyl, ethylsulfinyl, and the like.

The term “alkylsulfonyl” means a —SO₂R radical where R is alkyl asdefined above, e.g., methylsulfonyl, ethylsulfonyl, and the like.

The term “arylsulfinyl” means a —SOR radical where R is aryl as definedabove, e.g., phenylsulfinyl, and the like.

The term “arylsulfonyl” means a —SO₂R radical where R is aryl as definedabove, e.g., phenylsulfonyl, and the like.

The term “heteroarylsulfinyl” means a —SOR radical where R is heteroarylas defined above.

The term “heteroarylsulfonyl” means a —SO₂R radical where R isheteroaryl as defined above.

The term “alkoxycarbonyl” means an alkyl-O—C(O)— group, in which thealkyl group is as previously described.

The term “aryloxycarbonyl” means an aryl-O—C(O)— group, in which thearyl group is as previously described.

The term “heteroaryloxycarbonyl” means an heteroaryl-O—C(O)— group, inwhich the heteroaryl group is as previously described.

The term “cycloalkyloxy” means a —O-cycloalkyl group in which thecycloalkyl group is as previously described, e.g., cyclopropyloxy,cyclobutyloxy, cyclopentyloxy, cyclohexyloxy, and the like

The term “arylalkyloxy” means —O-(alkylene)-aryl group, in which thearyl and alkylene groups are as previously described.

The term “heteroarylalkyloxy” means —O-(alkylene)-heteroaryl group, inwhich the heteroaryl and alkylene groups are as previously described.

One of ordinary skill in the art will recognize that compounds of thepresent invention can exist in different tautomeric and geometricalisomeric forms. All of these compounds, including cis isomers, transisomers, diastereomic mixtures, racemates, nonracemic mixtures ofenantiomers, substantially pure, and pure enantiomers, are within thescope of the present invention. Substantially pure enantiomers containno more than 5% w/w of the corresponding opposite enantiomer, preferablyno more than 2%, most preferably no more than 1%.

The optical isomers can be obtained by resolution of the racemicmixtures according to conventional processes, for example, by theformation of diastereoisomeric salts using an optically active acid orbase or formation of covalent diastereomers. Examples of appropriateacids are tartaric, diacetyltartaric, dibenzoyltartaric,ditoluoyltartaric and camphorsulfonic acid. Mixtures of diastereoisomerscan be separated into their individual diastereomers on the basis oftheir physical and/or chemical differences by methods known to thoseskilled in the art with the benefit of this disclosure, for example, bychromatography or fractional crystallization. The optically active basesor acids are then liberated from the separated diastereomeric salts. Adifferent process for separation of optical isomers involves the use ofchiral chromatography (e.g., chiral HPLC columns), with or withoutconventional derivation, optimally chosen to maximize the separation ofthe enantiomers. Suitable chiral HPLC columns are manufactured byDiacel, e.g., Chiracel OD and Chiracel OJ among many others, allroutinely selectable. Enzymatic separations, with or withoutderivitization, are also useful. The optically active compounds of theinvention can likewise be obtained by utilizing optically activestarting materials in chiral synthesis processes under reactionconditions which do not cause racemization.

In addition, one of ordinary skill in the art will recognize that thecompounds can be used in different enriched isotopic forms, e.g.,enriched in the content of ²H, ³H, ¹¹C, ¹³C and/or ¹⁴C. In oneparticular embodiment, the compounds contain ²H. In another embodiment,the compounds contain ³H. Deuterated and tritiated compounds may beprepared using methods known in the art.

For example, deuterated forms can be made the procedure described inU.S. Pat. Nos. 5,846,514 and 6,334,997. As described in U.S. Pat. Nos.5,846,514 and 6,334,997, deuteration can improve the efficacy andincrease the duration of action, of drugs.

Deuterium substituted compounds can be synthesized using various methodssuch as described in: Dean, Dennis C.; Editor. Recent Advances in theSynthesis and Applications of Radiolabeled Compounds for Drug Discoveryand Development. [In: Curr., Pharm. Des., 2000; 6(10)](2000), 110 pp;Kabalka, George W.; Varma, Rajender S. The synthesis of radiolabeledcompounds via organometallic intermediates. Tetrahedron (1989), 45(21),6601-21; and Evans, E. Anthony. Synthesis of radiolabeled compounds, J.Radioanal. Chem. (1981), 64(1-2), 9-32.

Where applicable, the present invention also relates to useful forms ofthe compounds as disclosed herein, such as base free forms, andpharmaceutically acceptable salts or prodrugs of all the compounds ofthe present invention for which salts or prodrugs can be prepared.Pharmaceutically acceptable salts include those obtained by reacting themain compound, functioning as a base with an inorganic or organic acidto form a salt, for example, salts of hydrochloric acid, sulfuric acid,phosphoric acid, methane sulfonic acid, camphor sulfonic acid, oxalicacid, maleic acid, succinic acid, citric acid, formic acid, hydrobromicacid, benzoic acid, tartaric acid, fumaric acid, salicylic acid,mandelic acid, and carbonic acid. Pharmaceutically acceptable salts alsoinclude those in which the main compound functions as an acid and isreacted with an appropriate base to form, e.g., sodium, potassium,calcium, magnesium, ammonium, and choline salts. Those skilled in theart with the benefit of this disclosure will further recognize that acidaddition salts of the claimed compounds may be prepared by reaction ofthe compounds with the appropriate inorganic or organic acid via any ofa number of known methods. Alternatively, alkali and alkaline earthmetal salts can be prepared by reacting the compounds of the inventionwith the appropriate base via a variety of known methods.

The following are further examples of acid salts that can be obtained byreaction with inorganic or organic acids: acetates, aDIPEAtes,alginates, citrates, aspartates, benzoates, benzenesulfonates,bisulfates, butyrates, camphorates, digluconates,cyclopentanepropionates, dodecylsulfates, ethanesulfonates,glucoheptanoates, glycerophosphates, hemisulfates, heptanoates,hexanoates, fumarates, hydrobromides, hydroiodides,2-hydroxy-ethanesulfonates, lactates, maleates, methanesulfonates,nicotinates, 2-naphthalenesulfonates, oxalates, palmoates, pectinates,persulfates, 3-phenylpropionates, picrates, pivalates, propionates,succinates, tartrates, thiocyanates, tosylates, mesylates andundecanoates.

For example, the pharmaceutically acceptable salt can be ahydrochloride, a hydrobromide, a hydroformate, or a maleate.

Preferably, the salts formed are pharmaceutically acceptable foradministration to mammals. However, pharmaceutically unacceptable saltsof the compounds are suitable as intermediates, for example, forisolating the compound as a salt and then converting the salt back tothe free base compound by treatment with an alkaline reagent. The freebase can then, if desired, be converted to a pharmaceutically acceptableacid addition salt.

One of ordinary skill in the art will also recognize that some of thecompounds of the present invention can exist in different polymorphicforms. As known in the art, polymorphism is an ability of a compound tocrystallize as more than one distinct crystalline or “polymorphic”species. A polymorph is a solid crystalline phase of a compound with atleast two different arrangements or polymorphic forms of that compoundmolecule in the solid state. Polymorphic forms of any given compound aredefined by the same chemical formula or composition and are as distinctin chemical structure as crystalline structures of two differentchemical compounds.

One of ordinary skill in the art will further recognize that compoundsof the present invention can exist in different solvate forms. Solvatesof the compounds of the invention may also form when solvent moleculesare incorporated into the crystalline lattice structure of the compoundmolecule during the crystallization process.

The following examples are merely illustrative of the present inventionand should not be construed as limiting the scope of the invention inany way as many variations and equivalents that are encompassed by thepresent invention will become apparent to those skilled in the art uponreading the present disclosure. For example, some reactions describedbelow may be carried out under a range of conditions, such as at adifferent temperature (4° C., 10° C., 25° C., etc.), substitution withother reagents and different amounts or concentration of reagents.

EXAMPLES Example 1 Preparation of benzyl(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate (1:1)and analogs

The compounds of Formula (XVIII) (X═O, NH; R7=benzyl, ethyl) may beprepared as described below.

Example 1a

Benzyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) may be prepared as described below.

Dimethylsulfoxide (DMSO; 500 ml) was added to a mixture oftrimethylsulfoxonium iodide (ME₃SOI; 79.2 g, 360 mmol, 1.15 eq) andpotassium tert-butoxide (KOtBu; 38.6 g, 344.4 mmol, 1.1 eq) intetrahydrofuran (THF; 400 ml) at room temperature. The mixture wasstirred until the reaction was deemed to be complete and cooled to −12°C. A solution of (S)-5-oxo-pyrrolidine-1,2-dicarboxylic acid 2-benzylester 1-tert-butyl ester (100 g, 313.1 mmol, 1 eq) in tetrahydrofuran(THF; 300 ml) was added slowly. The mixture was stirred at −12° C. untilthe reaction was deemed to be complete. The reaction was quenched by theaddition of saturated aqueous ammonium chloride (500 ml) and water (300ml). The product was extracted with ethyl acetate (1000 ml), and theresulting organic solution was washed with aqueous sodium chloride. Theorganic layer was concentrated in vacuo to a final volume of 600 ml.

To this solution was added O-benzylhydroxylamine hydrochloride(BnONH₂HCl; 52.5 g, 328.8 mmol, 1.05 eq) and ethyl acetate (400 ml). Themixture was stirred at reflux until the reaction was deemed to becomplete. The mixture was cooled and washed with water and saturatedsodium chloride. The organic layer was concentrated in vacuo to afford asolution of(S)-5-Benzyloxyimino-2-tert-butoxycarbonylamino-6-chloro-hexanoic acidbenzyl ester in ethyl acetate.

Methane sulfonic acid (MSA; 61 ml, 939.3 mmol, 3 eq) was added to thissolution. The solution was stirred at 42° C. until the reaction wasdeemed to be complete. The solution was added to a solution of potassiumbicarbonate (156.7 g, 1565.5 mmol, 5 eq) in water (500 ml) and theresulting mixture was stirred vigorously at 52° C. until the reactionwas deemed to be complete. The organic layer was washed with aqueoussodium chloride and concentrated in vacuo to afford a solution of(S)-5-Benzyloxyimino-piperidine-2-carboxylic acid benzyl ester in ethylacetate.

Propanoic acid (140.6 ml, 1878.6 mmol, 6 eq) was added to a suspensionof sodium borohydride (23.2 g, 626.2 mmol, 2 eq) in ethyl acetate (600ml) and held until the reaction was deemed to be complete. The resultingsolution was added to a solution of benzyl(2S,)-5-[(benzyloxy)imino]piperidine-2-carboxylic acid benzyl ester inethyl acetate (600 ml total volume) and sulphuric acid (83.4 ml, 1565mmol, 5 eq) at −20° C. and held until reaction was deemed to becomplete. The reaction was quenched by the addition of water (1000 ml),then neutralized with aqueous ammonia solution. The organic layer waswashed with water and concentrated in vacuo to 400 ml. The solution waswarmed to 45° C. and held at this temperature. Methanol (200 ml) at 40°C. was added, followed by a freshly prepared solution of oxalic aciddihydrate (39.5 g, 313.1 mmol) in methanol (100 ml). The mixture wascooled and the product was isolated by filtration. The solid was washedwith an ethyl acetate/methanol mixture, then with ethyl acetate. Thesolid was dried to give benzyl(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate (1:1)as a single isomer (79.4 g, 185 mmol, 59%).

Example 1b

Benzyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) was prepared as a single isomer (SR) from a mixture of trans (SR)and cis (SS) isomers using the following procedure.

Benzyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) (100 g, 233 mmol, 70% SR isomer) was stirred in methanol (1.6 L)and heated to reflux. This temperature was maintained until all solidshad dissolved and a clear solution had formed. The solution was cooledto 25° C. over 2 h, and held at this temperature for 2 h. Theprecipitated solid was isolated by filtration, washed with methanol (200ml) and dried at 35° C. under vacuum for 16 h, to give benzyl(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate (1:1)as a white solid (65 g, 65% wt yield).

¹H NMR (400 MHz, DMSO) δ: 1.41 (1H, q), 1.69 (1H, q), 1.88 (1H, d), 2.17(1H, dd), 2.64 (1H, t), 3.11 (1H, m), 3.40 (1H, d), 4.00 (1H, dd), 4.58(2H, s), 5.23 (2H, s), 7.35 (10H, m).

Example 1c

Benzyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) may be prepared as described in Example 1a except as describedbelow.

Methane sulfonate salt of benzylhydroxylamine is used, causing theprocess to progress via an alternative intermediate, sulfoxonium oxime.Cyclization is carried out using triethylamine. Piperidine oxime isisolated as its p-toluenesulfonate (tosylate) salt.

Example 1d

(2S)-5-benzyloxyamino-piperidine-2-carboxylic acid benzylamide wasprepared as outlined below.

N,N′-Dicyclohexyl carbodiimide (DCC; 8.2 g, 40 mmol) was added to asolution of pyroglutamic acid (5.16 g, 40 mmol) in dimethylformamide(DMF; 60 ml). The mixture was stirred at room temperature for 2 h and aprecipitate formed. Benzylamine (4.8 ml, 44 mmol) was added and themixture was stirred for 2 h. t-butyl dicarbonate (Boc2O; 9.6 g, 44mmol), triethylamine (TEA; 6.3 ml, 44 mmol) and 4-dimethylaminopyridine(DMAP; 488 mg, 4 mmol) were added and the mixture was stirred at roomtemperature for 16 h. The DMF was removed under vacuum and the residuewas taken up with water (20 ml) and extracted with dichloromethane (DCM;3×20 ml). The organic layers were concentrated and the crude product waspurified via silica gel chromatography to afford(S)-2-benzylcarbamoyl-5-oxo-pyrrolidine-1-carboxylic acid tert-butylester (2.23 g, 7.0 mmol, 17.5%).

Dimethylsulfoxide (DMSO; 20 ml) was added dropwise to a suspension ofpotassium tert-butoxide (1.12 g, 10 mmol) and trimethylsulfoxoniumiodide (2.2 g, 10 mmol) in tetrahydrofuran (THF; 15 ml). The mixture wasstirred at room temperature for 1 h, then cooled to −10° C. A solutionof (S)-2-benzylcarbamoyl-5-oxo-pyrrolidine-1-carboxylic acid tert-butylester (1.59 g, 5 mmol) in THF (10 ml) was added, resulting in a whiteprecipitate. The mixture was stirred at 0° C. for 1 h. The reaction wasquenched with saturated NH₄Cl solution (20 ml), and the product wasextracted with EtOAc (2×50 ml). The organic layers were washed withbrine and concentrated under vacuum. The product was purified via silicagel chromatography (EtOAc/MeOH) to give the beta-ketosulfoxonium as awhite solid (615 mg, 1.5 mmol, 30%).

A slurry of the beta-ketosulfoxonium (584 mg, 1.42 mmol) andO-benzylhydroxylamine (251 mg, 1.57 mmol) in THF (20 ml) was refluxedfor 2 h. The mixture Was diluted with EtOAc (50 ml) and washed with 1NHCl (20 ml) and brine (20 ml). The product was purified via silica gelchromatography to give the chloro-oxime as a colorless oil (784 mg,quant).

The chloro-oxime oil was dissolved in EtOAc (10 ml) and methane sulfonicacid (320 μl, 4.95 mmol, 3 eq) was added. The mixture was stirred at 40°C. for 3 h. The mixture was poured into saturated sodium bicarbonatesolution (10 ml) and stirred at 50° C. for 2 h. The layers wereseparated and the organic layer was washed with water and concentratedto 10 ml. The solution was cooled to 0° C. Sulfuric acid (447 μl, 8.4mmol, 5 eq) was added, followed by sodium triacetoxyborohydride (712 mg,3.36 mmol). The mixture was stirred at 0° C. for 2 h. The reaction wasquenched with saturated sodium bicarbonate solution (20 ml). The layerswere separated and the organic layer was washed with water. The organiclayer was concentrated to 5 ml, and a solution of oxalic acid (153 mg,1.7 mmol) in ethylacetate (1 ml) and acetone (1 ml) was added. Theresulting solid was isolated by filtration, washed with EtOAc and driedunder vacuum at 35° C. to afford(2S)-5-benzyloxyamino-piperidine-2-carboxylic acid benzylamide as anoff-white solid (430 mg, 1.0 mmol, 71% from BKS N(Bn)).

Example 1e

Benzyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) was isolated from a mixture of trans (SR) and cis (SS) isomersusing the following procedure.

To a slurry of benzyl 5-[(benzyloxy)amino]piperidine-2-carboxylateethanedioate (1:1) (10 g, 23.3 mmol, 3:1, SR:SS) in ethyl acetate (70ml) was added a solution of potassium bicarbonate (9.3 g, 93 mmol, 4 eq)in water (90 ml). The mixture was stirred until all the solids haddissolved. The layers were separated and the aqueous layer was extractedwith ethyl acetate (30 ml). The combined organic layers were washed withwater (50 ml) and concentrated under vacuum below 40° C. to a finalvolume of 40 ml. The solution was passed through a filter and warmed to45° C. Methanol (20 ml) at 40° C. was added, followed by a freshlyprepared solution of oxalic acid dihydrate (3.67 g, 29.1 mmol) inmethanol (10 ml). The mixture was cooled and the product was isolated byfiltration. The solid was washed with an ethyl acetate/methanol mixture,then with ethyl acetate. The solid was dried to give benzyl(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate (1:1)as a single isomer (7.0 g, 16.3 mmol, 70%).

Example 1f

Ethyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) was prepared as described below.

A slurry of benzyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylateethanedioate (1:1) (100 g, 232 mmol) in ethanol (2000 ml) was cooled to0° C. A solution of sodium ethoxide in ethanol (216 ml, 580 mmol, 21 wt% solution) was added slowly and the mixture was stirred for 1 h at 0°C. Acetic acid (13.3 ml, 232 mmol) was added and the mixture wasconcentrated under vacuum below 35° C. to a final volume of 300 ml.Ethyl acetate (700 ml) was added and the mixture was concentrated to 300ml. This procedure was repeated twice. Water (1800 ml) was added to themixture followed by aqueous ammonia (variable) until the pH of theaqueous layer was 7.5 to 8. The layers were separated and the aqueouslayer was extracted with ethyl acetate (2×300 ml). The combined organiclayers were washed with water (500 ml) and concentrated to a finalvolume of 300 ml. The solution was filtered and diluted with ethylacetate (700 ml) and warmed to 35° C. A solution of oxalic aciddihydrate (30 g, 237 mmol) in acetone (200 ml) was added and the mixturewas cooled to room temperature. The solids were isolated by filtration,washed with ethyl acetate and dried under vacuum at 35° C. to obtainethyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) as a white solid (80.7 g, 94%).

Example 1g

Ethyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) was prepared as described below.

DMSO (120 ml) was added to a mixture of trimethylsulfoxonium iodide(20.5 g, 93.2 mmol, 1.2 eq) and potassium tert-butoxide (10.0 g, 89.4mmol, 1.15 eq) in tetrahydrofuran (100 ml) at room temperature. Themixture was stirred until the reaction was deemed to be complete andcooled to −12° C. A solution of (S)-5-oxo-pyrrolidine-1,2-dicarboxylicacid 2-ethyl ester 1-tert-butyl ester (20 g, 77.7 mmol, 1 eq) intetrahydrofuran (60 ml) was added slowly. The mixture was stirred at−12° C. until the reaction was deemed to be complete. The reaction wasquenched by the addition of saturated aqueous ammonium chloride (100 ml)and water (60 ml). The product was extracted with ethyl acetate (200ml), and the resulting organic solution was washed with aqueous sodiumchloride. The organic layer was concentrated in vacuo to a final volumeof 80 ml.

To this solution was added O-benzylhydroxylamine hydrochloride (13.0 g,81.6 mmol, 1.05 eq) and ethyl acetate (140 ml). The mixture was stirredat reflux until the reaction was deemed to be complete. The mixture wascooled and washed with water and saturated sodium chloride solution. Theorganic layer was concentrated in vacuo to 100 ml.

To this solution was added methane sulfonic acid (15.1 ml, 233.1 mmol, 3eq). The solution was stirred at 42° C. until the reaction was deemed tobe complete. The solution was added to a solution of potassiumbicarbonate (38.9 g, 388.5 mmol, 5 eq) in water (120 ml) and theresulting mixture was stirred vigorously at 52° C. until the reactionwas deemed to be complete. The organic layer was washed with aqueoussodium chloride and concentrated in vacuo to a final volume of 120 ml.

Propanoic acid (34.9 ml, 466.2 mmol, 6 eq) was added to a suspension ofsodium borohydride (5.75 g, 155.4 mmol, 2 eq) in ethyl acetate (160 ml)and held until the reaction was deemed to be complete. The resultingsolution was added to a solution of(S)-5-Benzyloxyimino-piperidine-2-carboxylic acid ethyl ester in ethylacetate (120 ml total volume) and sulfuric acid (20.7 ml, 388.5 mmol, 5eq) at −20° C. and held until reaction was deemed to be complete. Thereaction was quenched by the addition of water (240 ml), thenneutralized with aqueous ammonia solution. The organic layer was washedwith water and concentrated in vacuo to 80 ml. The solution was warmedto 45° C. and held at this temperature. Ethanol (80 ml, 95%) at 40° C.was added, followed by a freshly prepared solution of oxalic aciddihydrate (9.8 g, 77.7 mmol) in ethanol (40 ml). The mixture was cooledand the product was isolated by filtration. The solid was washed with anethyl acetate/ethanol mixture, then with ethyl acetate. The solid wasdried to give ethyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylateethanedioate (1:1) as a single isomer (16.4 g, 44.5 mmol, 57.3%).

¹H NMR (400 MHz, DMSO) δ: 1.22 (3H, t), 1.41 (1H, qd), 1.68 (1H, qd),1.88 (1H, m), 2.13 (1H, dd), 2.65 (1H, t), 3.13 (1H, m), 3.39 (1H, d),3.92 (1H, dd), 4.19 (2H, q), 4.59 (2H, s), 7.34 (5H, m).

Example 2 Preparation of(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxamide

(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxamide was prepared asdescribed below.

Example 2a

Benzyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) (50 g, 113.8 mmol) was mixed with a solution of ammonia inmethanol (7N, 700 ml) and agitated until the reaction was deemed to becomplete. The mixture was filtered to remove ammonium oxalate byproduct,the ammonium oxalate cake was washed with methanol (2×50 ml) and thecombined filtrates were concentrated to 250 ml. Toluene (500 ml) wasadded and the solution was concentrated to 250 ml causing the product toprecipitate. Toluene (500 ml) was added, and the mixture was heated to80° C. and cooled to 0° C. The product was isolated by filtration,washed with methyl tert-butyl ether (MTBE) (100 ml), and dried to yielda white crystalline solid (26.9 g, 108 mmol, 95%).

¹H NMR (400 MHz, DMSO) δ_(H) 1.12 (1H, m), 1.27 (1H, m), 1.83 (2H, m),2.22 (1H, dd), 2.76 (1H, m), 2.89 (1H, dd), 3.14 (1H, dd), 4.58 (2H, s),6.46 (1H, d), 6.91 (1H, s), 7.09 (1H, s), 7.32 (5H, m).

Example 2b

Benzyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) (50 g, 113.8 mmol) was mixed with a solution of ammonia inmethanol (7N, 700 ml) and agitated at ambient temperature until thereaction was deemed to be complete. The mixture was filtered to removeammonium oxalate byproduct and washed with methanol (2×50 ml) beforebeing concentrated to 250 ml. Toluene (500 ml) was added and thesolution was concentrated to 250 ml causing the product to precipitate.Cyclopentyl methyl ether (CPME) (500 ml) was added and the mixture washeated to 80° C. and then cooled to 0° C. The product was isolated byfiltration, washed with CPME (100 ml), and dried to yield a whitecrystalline solid (26.9 g, 108 mmol, 95%).

Example 2c

Benzyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) (100 g) was mixed with methanol (400 ml) and a solution of aqueousammonia (35%, 1 L) and agitated until the reaction was deemed to becomplete (18 h). The mixture was filtered to remove ammonium oxalatebyproduct and concentrated to 500 ml. Saturated aqueous brine solution(1.45 L) was added and mixture cooled to 0° C. The product was isolatedby filtration, washed with aqueous saturated brine solution (100 ml) at0° C., then ice cold water (2×50 ml), then methyl tert-butyl ether(MTBE) (100 ml), and dried to yield a white crystalline solid (38.6 g,68%).

Example 2d

Methyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) (1 g, 2.74 mmol) was mixed with a solution of ammonia in methanol(7N, 14 ml) and agitated at ambient temperature until the reaction wasdeemed to be complete. The mixture was filtered to remove ammoniumoxalate byproduct and washed with methanol (2×1 ml) before beingconcentrated to dryness (0.68 g, 2.72 mmol, 99%).

Example 2e

Ethyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) (10 g, 27.15 mmol) was mixed with a solution of ammonia inmethanol (7N, 140 ml) and agitated at ambient temperature until thereaction was deemed to be complete. The mixture was filtered to removeammonium oxalate byproduct and washed with methanol (2×50 ml) beforebeing concentrated to 50 ml. Toluene (50 ml) was added and the solutionwas concentrated to 50 ml causing the product to precipitate. Toluene(50 ml) was added and the mixture was heated to 80° C. and then cooledto 0° C. The product was isolated by filtration, washed with methyltert-butyl ether (MTBE) (2×15 ml), and dried to yield a whitecrystalline solid (6.29 g, 25.23 mmol, 93%).

Example 2f

(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxamide ethanedioate (1:1)was prepared as described below.

Benzyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate(1:1) (65 g, 148.0 mmol) was mixed with a solution of ammonia inmethanol (7N, 910 ml) and agitated at ambient temperature until thereaction was deemed to be complete. The mixture was filtered to removeammonium oxalate byproduct and washed with methanol (2×65 ml) beforebeing concentrated to 325 ml. Ethyl acetate (325 ml) was added followedby addition of a solution of oxalic acid (dihydrate) (20.52 g) in ethylacetate (325 ml) and methanol (32.5 ml) to crystallize the product. Theproduct was filtered and washed with ethyl acetate (2×195 ml), thendried to yield a white crystalline solid (49.3 g, 145.2 mmol, 98%).

¹H NMR (400 MHz, DMSO+TFA) δ_(H) 1.40 (1H, m), 1.61 (1H, m), 1.93 (1H,d), 2.22 (1H, d), 2.76 (1H, m), 3.22 (1H, m), 3.38 (1H, d), 3.70 (1H,t), 4.65 (2H, s), 7.35 (5H, m), 7.62 (1H, s), 7.88 (1H, s).

Example 3 Preparation of(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamide

(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamidewas prepared as described below.

Example 3a

(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxamide (102 g, 409 mmol)was mixed with di-isopropylethylamine (76.2 ml, 437.6 mmol) andchlorobenzene (612 ml) at 20° C. 9-fluorenylmethyl chloroformate (107.9g, 417.2 mmol) as a solution in chlorobenzene (612 ml) was added to thereaction mixture, and the mixture was stirred at 30° C. until thereaction was complete. Carbonyl diimidazole (86.2 g, 531.7 mmol) wasadded and agitation was continued until the reaction was deemed to becomplete. Diethylamine (105.8 ml, 1022.5 mmol) was added and agitationwas continued until the reaction was deemed to be complete. Aqueoushydrochloric acid (640 ml, 3N, 1920 mmol) was added and the mixture wascooled to 2° C. The solid was isolated by filtration, washed with water(2×200 ml) and 1-chlorobutane (2×200 mL) and dried to give the titlecompound as a white crystalline solid (101 g, 367.2 mmol, 90%).

¹H NMR (400 MHz, DMSO) δ_(H) 1.65 (2H, m), 1.83 (1H, m), 2.07 (1H, m),2.91 (2H, s), 3.63 (1H, s), 3.69 (1H, d), 4.92 (1H, d), 4.96 (1H, d),7.38 (7H, m).

Example 3b

(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamidewas prepared as described below.

A solution of potassium bicarbonate (47.5 g, 475 mmol) in water (250 ml)was added to a suspension of benzyl(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate (1:1)(50 g, 116 mmol) in 2-methyltetrahydrofuran (350 ml) and water (200 ml).The mixture was stirred until the reaction was deemed to be complete,and the layers were separated. The aqueous layer was extracted with2-methyltetrahydrofuran (100 ml) and the combined organic layers werewashed with water (150 ml). The organic layer was concentrated in vacuoand dried azeotropically to the desired water content. The solution wasdiluted with 2-methyltetrahydrofuran (800 ml) and cooled to 0° C.Triethylamine (42.4 ml, 309 mmol, 2.67 eq) was added, followed by asolution of triphosgene (15.1 g, 50.8 mmol, 0.44 eq) in2-methyltetrahydrofuran (200 ml). The mixture was stirred until thereaction was deemed to be complete. The reaction was quenched with asolution of potassium bicarbonate (24 g, 240 mmol, 2.07 eq) in water(300 ml). The layers were separated and the organic layer was washedwith aqueous sodium chloride solution. The organic layer wasconcentrated in vacuo, acetone was added and the solution wasconcentrated again. The solution was diluted with acetone (final volume900 ml), water (200 ml) was added, and the mixture was cooled to −12° C.A solution of lithium hydroxide monohydrate (7.8 g, 186 mmol, 1.6 eq) inwater (450 ml) was added slowly, and the mixture was stirred until thereaction was deemed to be complete. The reaction was quenched withaqueous hydrochloric acid to a final pH of 8.5. Toluene (500 ml) wasadded and the layers were separated. The aqueous layer was washed withtoluene (2×250 ml). Sodium chloride (60.5 g, 1000 mmol, 8.6 eq) wasadded, followed by dichloromethane (450 ml). Aqueous hydrochloric acidwas added until a final pH of 2.5 was achieved. The layers wereseparated and the aqueous layer was extracted with dichloromethane(2×150 ml). The combined organic layers were concentrated in vacuo anddried azeotropically. The resulting solution was diluted to 450 ml withdichloromethane and cooled to 0° C. Triethylamine (20 ml, 139 mmol, 1.2eq) was added, followed by trimethylacetyl chloride (14.2 ml, 116 mmol,1.0 eq). The mixture was stirred at 0° C. until the reaction was deemedto be complete. The mixture was cooled to −20° C. and quenched withaqueous ammonia (31 ml, 28%, 464 mmol, 4 eq). The mixture was stirred at0° C. until the reaction was deemed to be complete. Water (250 ml) wasadded and the layers were separated. The aqueous layer was extractedwith dichloromethane (100 ml). The combined organic layers were washedwith 2% aqueous ammonium chloride solution (2×250 ml) and concentratedin vacuo. Chlorobutane was added and the solution was concentrated invacuo. The resulting precipitate was collected by filtration, washedwith chlorobutane and dried under vacuum to give(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamideas a white solid (11.0 g, 40 mmol, 34.5%).

Example 3c

(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamidewas prepared as described below.

3-picoline (45 ml, 464, 4 eq) was added to a slurry of benzyl(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate (50 g,116 mmol, 1 eq) in dichloromethane (1000 ml) at 0° C., followed by asolution of triphosgene (31.0 g, 104.4 mmol, 0.9 eq) in dichloromethane(200 ml). The mixture was stirred at 0° C. until the reaction was deemedto be complete. The reaction was quenched with a solution of sodiumbicarbonate (24.4 g, 290 mmol, 2.5 eq) in water (300 ml), and the layerswere separated. The aqueous layer was extracted with dichloromethane(100 ml) and the combined organic layers were washed with water. Theorganic layer was concentrated in vacuo to give(2S,5R)-6-benzyloxy-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carboxylicacid benzyl ester as a solution in dichloromethane.

Aqueous tetrabutylammonium hydroxide (116 ml, 1.5 M, 174 mmol, 1.5 eq)was added to this solution at room temperature. The mixture was stirreduntil the reaction was deemed to be complete. The reaction was quenchedwith water and the pH was adjusted to 2.5 using HCl. The aqueous layerwas extracted and the combined organic layers were washed with water.The organic layer was concentrated in vacuo. Triethylamine (32.3 ml, 232mmol, 2 eq) and hexamethyldisilazane (72.6 ml, 348 mmol, 3 eq) wereadded to the resulting solution. A purchased solution of1-Propanephosphonic acid cyclic anhydride in ethyl acetate (69 ml, 116mmol, 1 eq, 50 wt % solution) was added to this mixture. The mixture wasstirred until the reaction was deemed to be complete. The reaction wasquenched with water and the organic layer was washed with aqueousammonium chloride solution. The organic layer was concentrated in vacuo.Chlorobutane was added and the solution was concentrated again causingthe product to crystallize. The solid was isolated by filtration, washedwith chlorobutane and dried under vacuum to give(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamideas a white solid (22.3 g, 81.1 mmol, 70%).

Example 3d

(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamidemay be prepared using an enzymatic approach as described below.

3-picoline (52.6 ml, 543 mmol, 4 eq) was added to a slurry of ethyl(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate (1:1)(50 g, 136 mmol, 1 eq) in dichloromethane (1000 ml) at 0° C., followedby a solution of triphosgene (36.4 g, 122.4 mmol, 0.9 eq) indichloromethane (200 ml). The mixture was stirred at 0° C. until thereaction was deemed to be complete. The reaction was quenched with asolution of sodium bicarbonate (28.6 g, 340 mmol, 2.5 eq) in water (300ml), and the layers were separated. The aqueous layer was extracted withdichloromethane (100 ml) and the combined organic layers were washedwith water. The organic layer was concentrated in vacuo to give(2S,5R)-6-benzyloxy-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carboxylicacid ethyl ester as a solution in dichloromethane (solution yield: 35 g,116 mmol, 85%). Acetonitrile was added and the solution was concentratedin vacuo to give(2S,5R)-6-benzyloxy-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carboxylicacid ethyl ester as a solution in acetonitrile. This solution wasdiluted with acetonitrile to 700 ml. To this was added ammoniumcarbamate (11.3 g, 145 mmol, 1.25 eq) and Novozyme 435 (35 g,immobilized Candida antarctica lipase B). The mixture was stirred at 40°C. until the reaction was deemed to be complete. The reaction mixturewas filtered and concentrated in vacuo. The solution was diluted withdichloromethane, washed with aqueous ammonium chloride, and concentratedin vacuo. Chlorobutane was added and the solution was concentrated invacuo. The precipitate was isolated by filtration, washed withchlorobutane and dried to give2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamideas a white solid (24.3 g, 88 mmol, 65% from ethyl(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylate ethanedioate).

Example 3e

(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamidewas prepared as described below.

Saturated aqueous potassium bicarbonate (30 ml) was added to a solutionof methyl (2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxylateethanedioate (1:1) (3.0 g, 8.38 mmol) in 2-methyltetrahydrofuran (25ml). The layers were separated and the organic phase was washed withsaturated aqueous sodium chloride solution (12.5 ml). The aqueous phasewas back extracted with 2-methyltetrahydrofuran (8.4 ml). The combinedorganic phases were concentrated to dryness, then reconstituted in2-methyltetrahydrofuran (75 ml). Triethylamine (3.1 ml) was added andthe solution was cooled to −5° C. Triphosgene (1.1 g) in2-methyltetrahydrofuran (16.8 ml) was added dropwise, maintaining atemperature <−3° C. The mixture was stirred for 1 hour beforedimethylaminopyridine (102 mg) was added. The mixture was held until thereaction was deemed to be complete. The reaction was quenched withsaturated aqueous potassium bicarbonate (21 ml). The layers wereseparated and the organic phase was washed with water (12.6 ml). Eachaqueous layer was back extracted with 2-methyltetrahydrofuran (12.6 ml).The combined organics were evaporated to dryness (3.51 g).

(2S,5R)-6-benzyloxy-7-oxo-1,6-diaza-bicyclo[3.2.1]octane-2-carboxylicacid methyl ester (0.767 g) was dissolved in acetonitrile (15.5 mL)containing ammonium carbamate (200 mg), Novozyme 435 (0.770 g,immobilized Candida antarctica lipase B) and calcium dichloride (0.244g). Ascarite II (2.4 g) was charged separately to the headspace. Themixture was stirred at 40° C. until the reaction was deemed to becomplete. The reaction mixture was filtered and concentrated in vacuo,before adding chlorobutane. The precipitate was isolated by filtrationin a centrifuge, washed with chlorobutane and dried to give2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazobicyclo[3.2.1]octane-2-carboxamideas a white solid (96% HPLC area).

Example 3f

(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamidewas prepared using N,N-Carbonyl diimidazole (CDI) as described below.

(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxamide (2 g) was mixedwith t-amyl alcohol (60 ml) and heated to 40° C. N,N-carbonyldiimidazole (CDI) (3.9 g) was added in portions over 1 hour and then themixture heated to 60° C. for 1 hour before concentrating under vacuum toapproximately half its volume. The mixture was cooled to 0° C., seeded,and held at 0° C. for 1.5 hours. The mixture was then filtered andwashed with MTBE (5 ml) before drying at 40° C. to yield a whitecrystalline solid (1.25 g, 56%)

Example 3g

2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamidewas prepared as described below.

(2S,5R)-5-[(benzyloxy)amino]piperidine-2-carboxamide (291 mg, 1.17 mmol)was mixed with triethylamine (193 □l, 1.37 mmol) and toluene (2.4 ml) at20° C. di-t-butyldicarbonate (310 mg, 1.42 mmol) as a solution intoluene (2.0 ml) was added to the reaction mixture, and the mixture wasstirred at 40° C. until the reaction was complete. The solution wasdiluted with toluene (3.9 mL) and carbonyl diimidazole (462 mg, 2.85mmol) was added and agitation was continued until the reaction wasdeemed to be complete. Methanesulfonic acid (663 □l, 10.2 mmol) wasadded and agitation was continued until the reaction was deemed to becomplete. After lowering the temperature to 20° C., aqueous potassiumhydrogen carbonate (10.2 ml, 1N, 10.2 mmol) was added and the mixturewas stirred at 20° C. until the reaction was complete. The aqueous layerwas separated and the toluene layer washed with water (3 mL), citricacid (1N, 3 mL) and water (3 mL). The four aqueous washes were twiceback-extracted with dichloromethane (2×3 mL). The three organic extractswere combined to give(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamideas a solution in toluene and dichloromethane (176 mg, 0.64 mmol, 55%).

Example 4 Preparation of tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanide

Example 4a

Tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanidewas prepared as described below.

(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamide(10 g, 36.2 mmol, 1 eq) was mixed with sulfur trioxide trimethylaminecomplex (6.07 g, 43.44 mmol, 1.2 eq), triethylamine (1.3 ml, 18 mmol,0.25 eq), palladium on carbon (0.8 g, 10% palladium, 50% water),isopropanol (50 ml) and water (50 ml). This mixture was treated withhydrogen until the reaction was deemed to be complete. The catalyst wasremoved by filtration and washed with water (20 ml). The combinedfiltrates were washed with n-BuOAc (70 ml, 20 ml) before a solution oftetrabutylammonium acetate (54.5 mmol) in water (20 ml) was added. Theproduct was extracted with dichloromethane (100 ml, 50 ml) and solventswapped into 4-methyl-2-pentanone, before filtering, washing and dryingto yield a white crystalline solid (16.9 g, 92%).

¹H NMR (400 MHz, CDCl3) δ_(H) 1.00 (12H, t), 1.45 (8H, m), 1.67 (9H, m),1.87 (1H, m), 2.16 (1H, m), 2.37 (1H, dd), 2.87 (1H, d), 3.31 (9H, m),3.91 (1H, d), 4.33 (1H, s), 5.79 (1H, s), 6.67 (1H, s).

Example 4b

Tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanidewas prepared as described below.

Palladium on carbon (400 mg, 5% Pd, 3% water) was added to a solution of(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamide(10.0 g, 36.2 mmol) in dimethylformamide (50 ml) and dichloromethane (50ml). The mixture was stirred under hydrogen atmosphere (3 atm) until thereaction was deemed to be complete. The catalyst was removed byfiltration and washed with a dimethylformamide/dichloromethane mixture(1:1, 40 ml). The combined filtrates were added to a solution ofchlorosulfonic acid (7.26 ml, 109.2 mmol 3 eq) in dimethylformamide (20ml) and dichloromethane (20 ml) at 20° C. The reaction mixture wasstirred until the reaction was deemed to be complete. The solution wasadded to ammonium bicarbonate (28.8 g, 364 mmol, 10 eq) in water (80 ml)maintaining a pH>6. Dichloromethane (50 ml) was added and the layerswere separated. The aqueous layer was washed with dichloromethane (2×100ml). A solution of ammonium bicarbonate (5.75 g, 72.8 mmol, 2 eq) inwater (60 ml) was added, followed by a solution of tetrabutylammoniumbisulfate (18.5 g, 54.6 mmol, 1.5 eq) in dichloromethane (100 ml). Thelayers were separated and the aqueous layer was extracted withdichloromethane (50 ml). The combined organic layers were washed withwater (50 ml) and concentrated in vacuo. 2-methylpentan-4-one was addedand the solution was concentrated in vacuo. The precipitate wascollected by filtration, washed with 2-methylpentan-4-one and driedunder vacuum to give tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanideas a white solid (11.14 g, 22 mmol, 60%).

Example 4c

Tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanidewas prepared as described below.

Palladium on carbon (1 g, 5% Pd, 3% wet) was added to a solution of(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamide(5 g, 18.2 mmol) in dimethylformamide (25 ml) and dichloromethane (50ml). The mixture was stirred under a hydrogen atm (3 bar) until thereaction was deemed to be complete. The catalyst was removed byfiltration and washed with a mixture of dimethylformamide (5 ml) anddichloromethane (10 ml). The combined filtrates were added to a solutionof SO3.DMF (5.58 g, 36.4 mmol) in acetic acid (20 ml). The mixture wasstirred until the reaction was deemed to be complete. Dichloromethane(100 ml) was added and the resulting precipitate was collected byfiltration. The precipitate was washed with dichloromethane (2×10 ml). Asolution of tetrabutylammonium acetate in water (23.7 ml, 1M, 23.7 mmol,1.3 eq) was added to the precipitate. The product was extracted withdichloromethane (50 ml, 10 ml), and the combined organic layers werewashed with water (10 ml). The organic layer was concentrated, dilutedwith 4-methyl-2-pentanone and concentrated again. The resultingprecipitate was collected by filtration, washed with cold4-methyl-2-pentanone and dried under vacuum to give tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanideas a white solid (6.33 g, 69%).

Example 4d

Tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanidewas prepared as described below.

A mixture of(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamide(10 g, 36.3 mmol), Pd/C (10%, 2 g, 0.2 parts), dichloromethane (50 ml)and dimethylformamide (50 ml) is stirred in a hydrogen atmosphere (3bar) for 3 h. The catalyst is removed by filtration through a cellulosepad and washed with DMF (20 ml). To the combined filtrates is added asolution of SO₃.DMF (5.07 g, 35.6 mmol) in DMF (15 ml). The mixture isstirred for 30 min at room temperature. The reaction mixture is analyzedby HPLC for consumption of the starting material. If necessary,additional SO₃.DMF in DMF is added and the mixture is stirred a further30 min. On completion of the reaction, the mixture is quenched by theaddition of a solution of tetrabutylammonium acetate (15 g, 49.8 mmol)in water (50 ml). The mixture is stirred for 2 h at room temperature.Xylenes (400 ml) is added and the mixture is concentrated under vacuumbelow 35° C. to a final volume of 50 ml. Xylenes (400 ml) is added andthe mixture is concentrated to a final volume of 35 ml. Water (20 ml) isadded and the mixture is allowed to settle. The organic layer isremoved. The aqueous layer is extracted with DCM (3×50 ml) and thecombined organic layers are washed with water (10 ml). The organic layeris treated with SC-40 carbon at reflux to remove palladium impurities.The carbon is removed by filtration. The organic layer is concentratedunder vacuum to a final volume of 50 ml. MIBK (50 ml) is added, and themixture is concentrated to a final volume of 50 ml. MIBK (130 ml) isadded and the mixture is concentrated to a final volume of 90 ml. Themixture is cooled to 0° C. and stirred for 3 h. The crystals arecollected by filtration, washed with cold MIBK (20 ml) and dried undervacuum at 45° C. to afford tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanide(11.2 g, 61%).

Example 4e

Tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanidewas prepared as described below.

(2S,5R)-6-(benzyloxy)-7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamide(60 g, 215.8 mmol, 1 eq) was mixed with sulfur trioxide trimethylaminecomplex (36.0 g, 258.9 mmol, 1.2 eq), triethylamine (7.52 ml, 53.9 mmol,0.25 eq), palladium on carbon (2.4 g, 10% palladium, 50% water),isopropanol (300 ml) and water (300 ml). This mixture was then heldunder hydrogen (1 bar) until the reaction was deemed to be complete. Thecatalyst was removed by filtration and washed with isopropanol (120 ml).The combined filtrates were added to a pre-mixed solution oftetrabutylammonium hydroxide (118 mmol, 1.15 eq), acetic acid (15.45 mL,270 mmol, 1.25 eq) and water (120 ml). The product solution wasconcentrated by distillation to remove isopropanol, and the product wasextracted with dichloromethane (360 ml, 120 ml) and solvent swapped into4-methyl-2-pentanone, before filtering, washing and drying to yield awhite crystalline solid (90.4 g, 79%).

Example 5 Preparation of Sodium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl)oxidanide(NXL-104)

Sodium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl)oxidanidewas prepared as described below.

Example 5a

Sodium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanide(NXL-104 Form I) was prepared as described below.

A solution of sodium ethyl hexanoate (32.8 g, 197 mmol, 2 eq) in ethanol(350 ml) was added to a seeded solution of tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanide(50 g, 98.7 mmol) in ethanol (315 ml) containing water (6.25 ml, 2% byvolume). The reaction mixture was held until reaction was deemed to becomplete. The product was filtered, washed and dried to yield a whitecrystalline solid (26.6 g, 94%).

¹H NMR (400 MHz, CDCl3) δ_(H) 1.65 (2H, m), 1.84 (1H, m), 2.07 (1H, m),2.93 (1H, d), 3.03 (1H, d), 3.69 (1H, d), 3.99 (1H, s), 7.27 (1H, s),7.43 (1H, s).

Example 5b

Sodium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanide(NXL-104 Form II) was prepared as described below

A solution of tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanide(10.1 g, 20 mmol) in isobutanol (48 ml) and water (2.5 ml) wastransferred to a 500 ml reactor via a 0.2 μm filter and warmed to 35° C.Separately, sodium 2-ethylhexanoate (6.7 g) was dissolved in isobutanol(49.5 ml) and water (0.5 ml) at 35° C. This solution was added to thesolution of tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanidevia a 0.2 μm filter over 1 h. The mixture was stirred 1 h at 35° C., 2 hat 25° C. and 2 h at 0° C. The mixture was filtered and the crystalswere washed with a mixture of isobutanol (19.5 ml) and water (0.5 ml).The crystals were dried under vacuum at 35° C. to afford a crystallineform (5.48 g, 90%).

Example 5c

Sodium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanide(NXL-104 Form I) was prepared as described below.

A solution of tetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanide(50 g, 98.7 mmol) in isobutanol (238 ml) and water (12.5 ml) wastransferred to a 1-liter reactor via a 0.2 μm filter and warmed to 35°C. Separately, a sodium 2-ethylhexanoate (33.3 g) was dissolved inisobutanol (250 ml) at 35° C. This solution was added to the solution oftetrabutylammonium({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl]oxidanideover 1 h. The mixture was stirred 1 h at 35° C., 2 h at 25° C. and 2 hat 0° C. The mixture was filtered and the crystals are washed with amixture of isobutanol (97.5 ml) and water (2.5 ml). The crystals wereresuspended in anhydrous EtOH (250 ml) and stirred at 35° C. for 4 h.The mixture was cooled to 0° C. and filtered. The crystals were washedwith EtOH (25 ml) and dried at 35° C. for 16 h to give 26.2 g (93%) ofNXL-104 as a fine white powder. XRD shows pure Form I. HELOS X₅₀=4.6 μm.

The present invention is not to be limited in scope by the specificembodiments described herein. Indeed, various modifications of theinvention in addition to those described herein will become apparent tothose skilled in the art from the foregoing description and theaccompanying figures. Such modifications are intended to fall within thescope of the appended claims. It is further to be understood that allvalues are approximate, and are provided for description.

All patents, patent applications, publications, product descriptions,and protocols are cited throughout this application, the disclosures ofwhich are incorporated herein by reference in their entireties for allpurposes.

What is claimed is:
 1. A process for preparing a compound of Formula(IX) comprising:

(a) treating a compound of Formula (XI)

with a source of ammonia or ammonia proxy to yield a compound of Formula(XIV):

(b) treating the compound of Formula (XIV) with a protecting group and acarbonylation agent to yield a compound of Formula (XVII):

(c) treating the compound of Formula (XVII) with a source of tetran-butylammonium ion to yield a compound of Formula (XIX):

(d) treating the compound of Formula (XIX) with a source of sodium;wherein R8 is selected from the group consisting of substituted orunsubstituted alkyl, allyl, aryl and benzyl and R9 is a hydroxylamineprotecting group.
 2. The process of claim 1, wherein R8 is selected fromthe group consisting of methyl, ethyl and benzyl.
 3. The process ofclaim 1, wherein R8 is benzyl.
 4. The process of claim 1, wherein R9 isselected from the group consisting of allyl and trialkylsilyl.
 5. Theprocess of claim 1, wherein R9 is benzyl.
 6. The process of claim 1,comprising treating the compound of Formula (XIV) with9-fluorenylmethoxycarbonyl.
 7. The process of claim 1, comprisingtreating the compound of Formula (XIV) with N,N-carbonyl diimidazole. 8.The process of claim 1, comprising treating the compound of Formula(XVII) with a SO₃ complex. 9.({[(2S,5R)-2-carbamoyl-7-oxo-1,6-diazabicyclo[3.2.1]oct-6-yl]oxy}sulphonyl)oxidanideprepared according to the process of claim 1.